Semiconductor manufacturing facilities often utilize a wafer cassette that is configured to contain a plurality of wafers. The wafer cassette may contain the wafers when they are stored and/or transferred among a plurality of wafer processing systems that may be utilized during a semiconductor manufacturing process. The wafer cassettes include a plurality of slots, and each of these slots is configured to contain a respective wafer therein. Generally, the integrity of the wafers within a given wafer cassette is maintained throughout the semiconductor manufacturing process to provide inventory control and/or to ensure that the wafers proceed through the various steps of the manufacturing process in a desired order. In other words, a given wafer might be removed from a given wafer cassette during processing of the wafer on a given wafer processing system. However, the given wafer will be returned to the given wafer cassette subsequent to completion of the processing. In addition, the given wafer cassette will not be removed from the given wafer processing system until each of the wafers that is present therein has been processed by the given wafer processing system and returned to the given wafer cassette.
In the manufacturing facility, the processing steps that are performed by the various wafer processing systems are typically automated and may require little or no user intervention for completion thereof. In addition, the manufacturing facility typically will utilize safeguards and/or interlocks to ensure that a given wafer is returned to its designated wafer cassette, to prevent unintentional interruption of a processing step on a given wafer, and/or to restrict combining wafers from different wafer cassettes into another wafer cassette.
However, and in a research and/or development environment, the wafer processing systems may be only partially automated and/or may require more user input for the operation thereof. In addition, the process operations that may be performed by these wafer processing systems may require a much longer period of time to complete than a period of time that might be required for a comparable manufacturing operation. As illustrative, non-exclusive examples, metrology and/or test systems that are utilized in the research and/or development environment may oversample the wafers in order to generate improved data sets and/or statistically relevant data. Under these conditions, a significant amount of time may be wasted if a user is not available to initiate a new process operation on a given wafer processing system immediately upon completion of a previous process operation on the given wafer processing system.
Thus, there exists a need for improved systems and methods for providing wafer access in a wafer processing system.